Compositions having isocyanate functional components are utilized to bond substrates together, such as, glass, often in the form of windows, into structures. In automotive assembly plants windows are bonded in with one part adhesive compositions containing isocyanate functional components, which cure by reaction with ambient moisture, and take several hours or days to cure. In the assembly plants, vehicles are not driven for several hours and this is acceptable. One part moisture curing adhesives known in the art are disclosed in U.S. Pat. Nos. 4,374,237; 4,687,533; 4,780,520; 5,063,269; 5,623,044; 5,603,798; 5,852,137; 5,922,809; 5,976,305; 5,852,137 and 6,512,033, relevant portions incorporated herein by reference.
Two-part compositions containing isocyanate functional prepolymers in one part and compounds having isocyanate reactive components in the other part are used where cure speed is important, such as in the automotive aftermarket replacement glass business. Customers desire that the adhesives cure quickly so that the vehicle can be driven as soon as possible after replacing the window. Examples of two-part compositions containing isocyanate functional prepolymers in one part and compounds having isocyanate reactive components in the other part are disclosed in EP 1,524,282, U.S. Pat. Nos. 5,852,103; 6,709,539; 7,101,950 and 7,361.292, relevant parts incorporated herein by reference. For certain applications even two part compositions containing isocyanate functional prepolymers do not cure fast enough for certain applications or customers. One solution is provided by commonly owned patent application titled DUAL CURE ADHESIVE USEFUL FOR BONDING TO GLASS, Jialanella U.S. patent application Ser. No. 13/455,294 filed Apr. 25, 2012, disclosing a composition comprising: a) one or more isocyanate functional prepolymers; b) one or more compounds containing a cycloaliphatic tertiary amine; c) one or more compounds containing a peroxide group; and d) and an acrylate containing component; and, one or more compounds containing one or more acrylate groups; wherein component a) and b) are kept separate from component c) until cure is desired. The cured compositions preferably demonstrate an adhesive strength as measured by lap shear strength according to SAE J1529 of 0.5 MPa or greater after 30 minutes from composition application or 0.25 MPa or greater after 15 minutes from adhesive application. The compositions are useful for bonding glass to other substrates, such as vehicles and buildings and parts of modular components together, such as vehicle modular components, relevant parts incorporated herein by reference.
Adhesive systems that allow for modification of properties to fit the environment of use or the substrates bonded are desired, such as relative elasticity and modulus. Manufacturers desire to handle products as soon as possible to enhance productivity. In modern industrial processes, there is a need to move parts and to place loads on adhesive systems as soon as possible. Adhesives which have a good green strength shortly after application and exhibit longer open time are needed. Open time is the time from contacting the two parts of a composition together until the composition can no longer adhere to a substrate. Open time is important because some time is needed to assemble the parts to be bonded together in the proper arrangement, sometimes the parts need to be adjusted after assembly to achieve the desired arrangement.
Even with the advancements in the art described herein there is a need for even faster curing systems that afford reasonable open times. Thus, what are needed are adhesive systems which exhibit good green strength, even more rapid cure rates, the ability to allow substrates to be handled shortly after application of the adhesive system and sufficient open times to allow proper placement of the parts bonded together. What are also needed are adhesive systems wherein the properties can be adjusted to meet the needs of a particular substrate system.